Untreated engine emissions, such as those generated by a diesel engine for example, include hydrocarbons, carbon monoxide, and other carbon based particulate matter which is also referred to as “soot.” Vehicle exhaust systems include exhaust after-treatment devices that filter these contaminants. These devices include emission abatement components such as filters/traps that collect the contaminants. Periodically, the filter or trap is regenerated with a fuel-fired burner which burns off the collected matter.
State and federal regulations require that diesel engine exhaust after-treatment devices include diagnostics to detect system problems, and also require that these diagnostics be able to identify which component within the system is faulty.